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SizedBox

Gives a widget fixed dimensions, or acts as a spacer when used without a child.

Basic Usage​

// Fixed size
widgets.SizedBox{
    Width:  100,
    Height: 50,
    Child:  content,
}

// Width only
widgets.SizedBox{
    Width: 200,
    Child: content,
}

// Fixed-size spacer (no child)
widgets.SizedBox{Height: 16}

Properties​

PropertyTypeDescription
Widthfloat64Fixed width in pixels (0 means unconstrained)
Heightfloat64Fixed height in pixels (0 means unconstrained)
Childcore.WidgetOptional child widget

Common Patterns​

Fixed-Size Spacer​

widgets.Column{
    MainAxisSize: widgets.MainAxisSizeMin,
    Children: []core.Widget{
        header,
        widgets.SizedBox{Height: 16},
        body,
    },
}

The VSpace and HSpace helpers are shorthand for this pattern:

widgets.VSpace(16)  // equivalent to SizedBox{Height: 16}
widgets.HSpace(8)   // equivalent to SizedBox{Width: 8}

To fill remaining space in a Row or Column, use Spacer() instead:

widgets.Row{
    Children: []core.Widget{
        label,
        widgets.Spacer(),  // fills remaining horizontal space
        button,
    },
}

See Expanded & Flexible for more on flexible space distribution.

Constraining Child Size​

// Limit an image to 200x200
widgets.SizedBox{
    Width:  200,
    Height: 200,
    Child:  profileImage,
}